#$@#$@#$$!$!!!!!

[Stage1 Jeff]

decided to replace the NGK BP5ES plugs in my 430 with some fresh NGK FR5 V power plugs before cruising season.
I noticed all the old plugs were carbon fouled,which I would think indicates it is running rich. my holley 770 street avenger has a 6.5 power valve, 72 front jets, 75 rear jets. accelerator pump cam is brown. floats set correctly. ignition is MSD 6A, MSD Pro Billet dist, Blaster 2 coil
I have been fighting with this problem since the day I put it on in 2003. electric choke appears to be working,with key on it opens like it should. WTF can I do to solve my problem???

[nailheadina67]

Throw that holley in the can and get a real carb. :pp

I tried one on a Ford I used to own and had nothing but problems with it. Holley's are sloppy carbs IMHO, but then I'm no carburetion expert either. The best running carb I ever had was my old Quardajet, after I was able to get it to stop leaking. :Dou:

[Stage1 Jeff]

I'm not going to switch to a q jet, or edelcrock carb .
there's got to be someone out there who can tell me how to get it to work as intended

[DaWildcat]

decided to replace the NGK BP5ES plugs in my 430 with some fresh NGK FR5 V power plugs before cruising season.
I noticed all the old plugs were carbon fouled,which I would think indicates it is running rich. my holley 770 street avenger has a 6.5 power valve, 72 front jets, 75 rear jets. accelerator pump cam is brown. floats set correctly. ignition is MSD 6A, MSD Pro Billet dist, Blaster 2 coil
I have been fighting with this problem since the day I put it on in 2003. electric choke appears to be working,with key on it opens like it should. WTF can I do to solve my problem???

What's the manifold vacuum read at idle, in gear? Just wondering if a big camshaft might have the power valve(s) opening too early.

Devon

[Stage1 Jeff]

the cam is a TA 310. if I remember right, the vacuum reading in gear at idle was 15-17" (can't remember exactly)
no power brakes

[DaWildcat]

That valve should stay closed, then. Hmmmm...another possibility is a torn power valve diaphragm, even though the new Holleys have a better design that resists backfire damage. Might be worth a look to see regardless.

Devon

[Stage1 Jeff]

the 6.5 in it now is a fairly new one, hasn't had a backfire to blow it
unless I ought to change the pump cam? maybe it's opening it too soon??

[DaWildcat]

the 6.5 in it now is a fairly new one, hasn't had a backfire to blow it
unless I ought to change the pump cam? maybe it's opening it too soon??

Accel pump cam shouldn't cause a constantly rich mix. Power valve was my only guess, since your primary jetting seems decent for your engine. :Do No:

Does the carb respond to idle mix screw adjustment? You should be able to stall it by turning them in.

Devon

[Stage1 Jeff]

last time I had a good friend look at it, he turned them in one at a time, and it did come close to stalling, he immeadiately turned them out 3 and a half turns
won't be taking it out for a few weeks.

[sore loser]

Jeff,

If it's not the power valve, did you consider a warped main body? Did you buy your carb new? Also, if the check valve is not installed or dirty under the accelerator pump outlet then raw fuel can be drawn into the bores. Those are about the only three ways fuel can get into the manifold. Try buying or borrowing one of the Holley books, they can help temendously. Good Luck!

[Stage1 Jeff]

Jeff,

If it's not the power valve, did you consider a warped main body? Did you buy your carb new? Also, if the check valve is not installed or dirty under the accelerator pump outlet then raw fuel can be drawn into the bores. Those are about the only three ways fuel can get into the manifold. Try buying or borrowing one of the Holley books, they can help temendously. Good Luck!

yes, I bought it new in 2003,wonder if those main bodies are the same? I have the main body off a 600 I could use. I doubt if holley would replace the main body if it was warped. I will check to see if the check valve is ok.

I'll definately check into getting a holley book :) thanks!

[jeff bullock]

Jeff,did you try running your mixture screws in a half to three quarters of a turn to see what that does? It also might make a difference once you get your new plugs in there and open the gaps up a little more to see what that does.

[Stage1 Jeff]

I'll try that when I take it out in a few weeks, am still putting trim pieces,and other things back on it after paint.new plugs gapped at .045.
I'll have to look my carb up online, to see what the check valve looks like

[7 skylark 1]

warm up the engine. hook a vacuum gauge up to manifold vacuum and adjust the mixture screws for highest reading.

[Stage1 Jeff]

took an old 600 accel pump apart, found a check ball there above the diaphram.
is this what I should inspect to see if it fell out,or is dirty??

[Mr BB Chevy]

what size & type of exhaust? are the throttle plates opened passed the idle circuit?
how about coming down on the jets? 68/71 and dropping the pv to a 4.5

[Stage1 Jeff]

what size & type of exhaust? are the throttle plates opened passed the idle circuit?
how about coming down on the jets? 68/71 and dropping the pv to a 4.5

3.5" w/X pipe, 3" walker CVX mufflers
I will look and see about the throttle plates
I'll see about the jets/pv too.(I did try a 3.5 pv, no change)
still pulls hard and strong though

this carb has had problems since new, had same problem in another car, it had 3" pipe on it

[sore loser]

Take out the shooter(s) and turn the carb upside down carefully the check valve should fall out. I dont know if it's a ball or a needle.

[Stage1 Jeff]

I'll do that
I might go down on the shooter sise too, I think I have a #37 in it now

[sore loser]

A number 37 is probably very close. Changing the shooter won't help a "rich all the time problem". you should only change the shooter to cure a stumbling problem. I would look for things that cause excess fuel to enter the manifold or things that prevent airflow.

[Stage1 Jeff]

the rich condition is mainly when cold/first start of day.(choke seems to be working) after a few miles, it clears up, I never see black smoke when driving. (I forgot to mention that in the first post)
but I think I will go ahead and drop down to the $68,and #71 jets,and the 4.5 pv

[nailheadina67]

the rich condition is mainly when cold/first start of day.(choke seems to be working) after a few miles, it clears up, I never see black smoke when driving. (I forgot to mention that in the first post)

Jeff......it sounds like you are having the same problem with your carb as I did with mine (it was a 600 with vac secondaries). It seemed no matter what I did, it would run very rich on start up on cold, humid days but lean on warm, dry days. Sometimes I would have to restart it once or twice b/c it would stall immediately after starting it when cold. After trial and error I was finally able to find a compromise adjustment......but I was never happy with that b/c it was never really right. If your carb is running rich when cold but OK when at normal temp, you have a choke related problem. Jetting probably won't help. Perhaps someone has the solution for your problem, but I ran that holley on my Ford for over 8 years and was never able to get it to run perfect. Even when it was new out of the box, I had flooding problems that were difficult to fix......I had to use heavier springs on the floats. Maybe you could try that?

[Stage1 Jeff]

I don't think the avenger series had the springs, the old 600 parts carb I have has the springs. wonder if my floats could possibly have a hole in them?
front one is brass, secondary is some type of plastic. just a thought

[oilmilk]

I would try dropping 2 jet sizes all the way around and see if the plugs clean up. Also make sure you are getting 12 volts to your msd. Good luck.

[Stage1 Jeff]

I would try dropping 2 jet sizes all the way around and see if the plugs clean up. Also make sure you are getting 12 volts to your msd. Good luck.

I hadn't thought of the ignition not getting full 12v. I think have it going to an ign terminal in the fuse block, I'll sure check that out!!!! thanks! :TU:

[sore loser]

Do you have an electric fuel pump? Regulated 4.5-6 lbs? It could be pushing the needle off the seat.

[Stage1 Jeff]

yes I do, it shows just over 5 psi on my gauge

[sore loser]

Any chance your heat crossover in the heads/manifold is blocked with carbon or intentionally? Without this heat under the manifold the fuel won't atomize correctly and seems rich during warm-up. I blocked the ports in the heads on a sbb years ago then reversed the process because the cold start problems were not worth the small power gains.

[Stage1 Jeff]

shouldn't be blocked with carbon, engine has just over 600 miles ( SE Stage 1 alum heads,SP1 intake)
I don't recall plugging them.(I felt the intake once a couple min. after the engine was started,it was warming up as the engine ran
for now,I'll concentrate on re jetting the carb, and make sure I have 12v to my MSD box,and then see what it does

[Rick Henderson]

Jeff,
What kind of air cleaner and base do you have? Is it a drop base by chance?

[Stage1 Jeff]

yes, it is

[freak6264]

I've read all your posts- look at your choke again. Adjust per the Holley manual.

[Stage1 Jeff]

was going to check to see if choke was getting full 12v with key on, while I'm checking things out

[freak6264]

not so much the voltage- making sure it's adjusted to the correct position cold- had problems when I first threw mine on too!

[Stage1 Jeff]

I'll go over it again :)

[jeff bullock]

The linkage isn't interfering with the underside of the air cleaner is it ?

[Stage1 Jeff]

not real sure, I'll look.
I really want to make an "air box" to match my cowl hood. anyone got a plan for one I could folllow? something that could be built for cheap?

[jeff bullock]

Just measure everything,get ya some sheet metal and aviation snips or air shears and a pop rivet gun and go to town with your imagination.:Brow:

[Rick Henderson]

Jeff,
What kind of air cleaner and base do you have? Is it a drop base by chance?


yes, it is

The reason that I asked is because I had a drop base air cleaner on my setup. I found that whatever I did, it was too rich. If you look, you will notice that the vents are not being able to vent under the top of the air cleaner cover. As soon as I took off the air cleaner, the car ran much better.

Actually, I put the Stage 2 type cowl scoop on it and it solved that. Well some of it.

The other problem that I found out was that HOLLEY put a 750 base on the 1000 carb that I bought brand new from Summit. That put a monkey wrench in it too. Their tech department manager has it on his desk and said that it is there to show the crew that they are human too, he said.

[Johnny Angel]

The reason that I asked is because I had a drop base air cleaner on my setup. I found that whatever I did, it was too rich. If you look, you will notice that the vents are not being able to vent under the top of the air cleaner cover. As soon as I took off the air cleaner, the car ran much better.

Actually, I put the Stage 2 type cowl scoop on it and it solved that. Well some of it.

The other problem that I found out was that HOLLEY put a 750 base on the 1000 carb that I bought brand new from Summit. That put a monkey wrench in it too. Their tech department manager has it on his desk and said that it is there to show the crew that they are human too, he said.

Rick,

How much of a gap do you need between the aircleaner top and the vents?

Regards, John.

[Rick Henderson]

I am not sure on the exact distance on the vent to top, but I did hear of some folks cutting them down a bit. I am sure someone will chime in that knows the correct answer.

I had a 2-3 inch drop base (don't remember for sure), so it was really close on the vents. I even switched to a top that had the screen on the top, and it still had the same problem with being too rich with the cover on.

[Stage1 Jeff]

The reason that I asked is because I had a drop base air cleaner on my setup. I found that whatever I did, it was too rich. If you look, you will notice that the vents are not being able to vent under the top of the air cleaner cover. As soon as I took off the air cleaner, the car ran much better.

Actually, I put the Stage 2 type cowl scoop on it and it solved that. Well some of it.

The other problem that I found out was that HOLLEY put a 750 base on the 1000 carb that I bought brand new from Summit. That put a monkey wrench in it too. Their tech department manager has it on his desk and said that it is

there to show the crew that they are human too, he said.

I hadn't thought of that..... so where can I find the right air cleaner?? anyone got an extra one I can have??
here's a pic of my setup, are these the vents?? circled in pic

[Johnny Angel]

Boy Jeff, I would sure hope you have enough space. Your filter looks to be 3 or 4 inches tall. I for one will be watching your thread, because I have a new engine going in, with a drop base, that looks like yours. I will be using a 3 inch filter for hood clearance. Good luck.


Regards, John.:Do No:

[DaWildcat]

I hadn't thought of that..... so where can I find the right air cleaner?? anyone got an extra one I can have??
here's a pic of my setup, are these the vents?? circled in pic

Yes, those are the vents. With that drop base you'll have plenty of vent clearance even with a flat lid. Holley suggests no less than 3/4" clearance above the vent.

Devon

[Stage1 Jeff]

Yes, those are the vents. With that drop base you'll have plenty of vent clearance even with a flat lid. Holley suggests no less than 3/4" clearance above the vent.

Devon

so,My current set up is ok?? I may try making an air box, would it also require an air filter? I may go as far, as to remove the choke plate completely,or would doing so cause me more problems?

[Rick Henderson]

You have PLENTY of room. Mine was less than a 1/4" or touching on the lid. Well, it rules that out.

[Stage1 Jeff]

yep, it sure does.
so I guess it's concentrate on jetting down, check voltage to the choke/adjust it,check voltage to my MSD box. am tempted to do away with the choke altogether

[gsxbuildernut]

I can remember having the same problems on my 66 nova with a holley 750, I never did get it to tune lean enough and I changed everything. I put a demon on it and the exhaust smelled like it would pass emisions and the plugs cleaned up to the point I was worried about being too lean. I will not buy a holley again because it wasn't the first carb to give me fits. I'm sure there are great ones but I haven't owned one of them. I have heard that there are problems in some of the metering plates when they are the cast type, hard to say but I feel your pain. Hope you figure it out. The past three engines I have done recieved Demons and so far I never had to break one down to change anything. Good luck!!


Steve :TU:

[Stage1 Jeff]

thanks!!
I'll keep at till I get it the way I want it :TU:

[Schurkey]

1. WHEN is the carb rich? Idle? Cruise? WFO? Cold? Warm?

2. Are the idle mixture screws set to 3 1/2 turns because that's where the engine runs best, or because it seemed like a good number of turns?

3. I've never seen a Holley choke pulloff piston that was adjusted right from the factory. Guys go nuts cranking the choke coil trying to fix "gargles on gasoline just after cold startup" and the choke coil isn't the problem--it's the pulloff piston. What makes this even more fun is that Holley has practically buried the instructions for adjusting the piston--and they're not even included when you buy an electric choke conversion kit from 'em.

Overall, I get the feeling that adjusting the idle mix and the pulloff piston would clear up a lot of your trouble.

I'll have to dig around to find the link to the pulloff adjustment instructions.

[Stage1 Jeff]

1. WHEN is the carb rich? Idle? Cruise? WFO? Cold? Warm?

2. Are the idle mixture screws set to 3 1/2 turns because that's where the engine runs best, or because it seemed like a good number of turns?

3. I've never seen a Holley choke pulloff piston that was adjusted right from the factory. Guys go nuts cranking the choke coil trying to fix "gargles on gasoline just after cold startup" and the choke coil isn't the problem--it's the pulloff piston. What makes this even more fun is that Holley has practically buried the instructions for adjusting the piston--and they're not even included when you buy an electric choke conversion kit from 'em.

Overall, I get the feeling that adjusting the idle mix and the pulloff piston would clear up a lot of your trouble.

I'll have to dig around to find the link to the pulloff adjustment instructions.

1. problem is when cold, first start of day. plugs carbon fouled
2.mixture screws were set 3 1/2 turns using vacuum gauge,engine ran good(I could re do them if I have to)

[doc]

With a holley, float level ,power valve, choke setting, and the bleed orfice determines how rich or lean the carb will run. Now, that said, you have set the float level, and the power valve is ok, I would open up the primary air bleeds until the carb leans out. BE VERY CAREFULL WHEN DOING THIS. GO SLOWLY, the air bleeds determine how much air is mixed with the fuel in the idle circuit and if you drill out too big the only way you can correct is by soldering up and redrilling. or get new ones from holley.
When you set the choke use a 1/8 drill as a gage, placing it at the bottom of the choke plate against the carb body. You might consider using a different spark plug. suggest motor craft or autolite.

[Stage1 Jeff]

I already have a fresh set of NGK FR5 V power plugs in it now. I had these on hand, so I'll run these for now